JPH0667604B2 - Cover cloth for protective clothing, method for producing the same, and test method - Google Patents

Abstract

A coated product is provided that is comprised of a substrate and a coating comprised of a microporous scaffold material having a high void volume and open, interconnecting void microstructure, the scaffold material having a layer of a selected polyurethane thereon which extends in the voids. The coated product has good barrier properties with respect to bacteria, viruses, and air-borne particulate.

Description

Description: FIELD OF THE INVENTION The present invention relates to new forms of coated fabrics and methods of making the same. More particularly, the present invention relates to such fabrics that provide barrier protection against microorganisms such as bacteria and viruses and airborne particulates.

BACKGROUND OF THE INVENTION Surgical gowns, drapes, etc. protect surgically prepared areas of skin from contamination and also protect surgeons and nurses from contact with unprepared or contaminated areas of the patient's skin. To do. Additionally, the surgical gown should provide a sterile barrier that protects the patient from contamination from contact with the surgeon and vice versa.

Liquid impermeability of the gown or drape is recognized as an important property in that it ensures that the gown or drape provides a sterile surface and yet acts as a barrier to the passage of bacteria or viruses. Bodily fluids and other liquids can penetrate through the surgical gown or drape and come into contact with the patient's skin. Thus, viruses and bacteria, such as the AIDS virus, present on the surface of the gown or drape may be transferred through the gown to the patient or person in the operating room.

In addition to being liquid repellent and a barrier to bacteria and viruses, hospital gowns provide a dazzling outer surface, yet are preferably non-fluffy, have antistatic properties, and are comfortable to wear. It's not a little important.

It was widely accepted that clothing should be "breathable" in order to be comfortable to wear. However, since the clothes are comfortable to wear, it is not necessary for the air to pass through the clothes, and the water vapor from perspiration permeates from the inside to the outside, so that the underwear does not get wet and a natural evaporative cooling effect is obtained. It is only necessary to be done. Breathability and the ability to transfer internal water vapor to the external environment are used interchangeably herein. A continuous film of hydrophilic material is exposed to air containing significant water vapor on one side of the film,
When exposed to air containing less water vapor on the other side, the side of the film exposed to the higher water vapor concentration diffuses into the film and is desorbed or vaporized on the side exposed to the lower water vapor concentration. Absorbs water molecules. Thus
Water vapor is effectively transported through the film based on one molecule. This property is known as "breathability".

One type of commonly used protective garment is made from a polyolefin nonwoven substrate. Garments made from this material have considerable protective properties, but are known to be very uncomfortable due to their inherent low moisture permeability, ie their low breathability. Various attempts have been made to improve the breathability of this nonwoven material. However, these efforts often lead to a more open structure of the non-woven material, thus also simultaneously reducing its protective value. Nonwoven polyolefin coatings have been used to provide greater barrier protection to nonwoven "open" substrate structures. However, the already inherently low moisture permeation properties of the non-woven material are even further reduced, while at the same time reducing the comfort of the garment made using this technique.

Protective clothing in hospital operating rooms was made from spunlaced polyester, which was heavily treated with water repellent and filled with wood pulp.
Here, too, a compromise of nature needs to be reached. Greater comfort will sacrifice the best microbial barrier protection, and greater barrier protection will reduce comfort. For example, when a hospital operating room down product requires better protection from microorganisms than the base spunlaced polyester, a polyethylene film is usually laminated to the polyester. However, while achieving good barrier properties, water vapor transmission is significantly reduced.

As can be seen from the above description, the protection characteristic and the comfortability characteristic are exchanged with each other. The present invention provides highly desirable barrier protection properties while at the same time achieving good water vapor transmission properties, ie both protection and comfort.

SUMMARY OF THE INVENTION A combination of porous scaffold material, hydrophilic polyurethane resin, and substrate, all in proper relationship to each other, has a desirable aesthetics and a coated product having beneficial microbial and particulate barrier properties. The discovery was made to bring. In particular, the coated product provides a functional barrier without compromising the comfort of the wearer. A given functional buyer serves as an effective barrier against microorganisms and airborne particulates.

In the present invention, the coating is applied to one side of the substrate in a special way to provide the desired barrier properties. The coating is a combination of both a polymeric microporous scaffold layer and a hydrophilic polyurethane resin.

Thus, the product of the present invention have (a) at least 5000g / m ^2/24 hours, preferably at least 10,000g / m ^2/24 hours, and most preferably a water vapor transmission rate of at least 15,000g / m ^2/24 hours Base cloth,
And (b) a coating on at least one surface of the base fabric, comprising a polymeric porous scaffold material having an open continuous pore microstructure, the scaffold material having a porosity of the entire scaffold material. At least 65% of the volume of said scaffold has a weight of 1 to 10 g per square meter,
The scaffold has a layer of hydrophilic polyurethane resin on one surface of the scaffold, which layer extends into some of the pores of the scaffold, and the polyurethane layer is 5-25
g / m ^2, preferably has a weight of 10 to 20 g / m ^2, the coating is applied to the base fabric on the surface containing the resin, a coated fabric comprising said coatings , The coated fabric is a microbial barrier that does not allow passage of viruses when tested by the Virus Barrier Efficiency Test (VBET) at 0.28 kg / cm ² (4 psi), and it is Gurley air. It is a coated fabric characterized by being an airborne particulate barrier that exhibits an air permeability of less than 6 cc / min in a permeability test.

The surface of the coated fabric has a pleasing appearance due to the fact that the polyurethane resin does not fill the pores of the scaffold to the extent that the polyurethane resin is on the opposite side of the scaffold. Also, a second layer of untreated scaffold may be applied to the surface to ensure that there is an exposed microporous surface on the opposite side.

The products of the present invention are continuous coatings and as such are not substantially air permeable, thus providing a barrier to airborne particulates. Further, the product of the present invention is
Acts as a barrier against microorganisms such as viruses and bacteria. These barrier properties are achieved when the water vapor transmission rate (MVTR) of the coated product is slightly lower than the MVTR of the uncoated raw substrate. Thus, the products of the present invention provide both protection and comfort, maximizing both without compromising either. Notably, these features are also retained after gamma sterilization.

Also provided is a method of making a coated product comprising combining the coating with a base fabric.

Also provided is a method of testing a coated product with a virus to determine the functional integrity of the coating.

DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 show the configuration of one embodiment of the present invention.

3 and 4 show diagrams of machines used to test coated fabrics for viral barrier efficiency.

FIG. 5 shows a schematic diagram of the process used in the present invention.

FIG. 6 is a scanning electron micrograph of the product of the present invention.

DETAILED DESCRIPTION OF THE INVENTION As used herein, a coated article or coated fabric is one or more materials that provide the substrate with properties that the substrate does not have on its own, continuously coated on the surface. Is.

The substrate used in the present invention is at least 5000g / m ^2/24
It can be any fabric that has a water vapor transmission rate over time. The fabric may be woven, non-woven or knitted fabric. It may also have the form of a scrim, mesh or grid. In applications such as hospital gowns, nonwoven materials such as polyester-cotton blends, woven fabrics, or wood pulp are often used as substrates.

Polymer scaffold material has open porosity and 65%
It is a microporous polymer having a microstructure of higher porosity. It may be preferred for some applications to have a porosity of greater than 70% or even greater than 85%. The scaffold material may have a thickness of less than 100 microns, preferably less than 35 microns, most preferably less than 20 microns.

Scaffold materials include films of microporous polyolefins such as polytetrafluoroethylene, polypropylene, polyethylene and other microporous polymers with high water vapor transmission rates.

The preferred scaffold material is expanded polytetrafluoroethylene (PTFE). This material is characterized by open open pores, high strength, and stable chemical multiplicity. U.S. Pat.No. 3,953,566 and 4,187,390
The specification discloses the preparation of desirable microporous expanded polytetrafluoroethylene films. These films are commercially available from WL Gore & Associates, Inc. (Gore & Associates, Inc.) and are sold under the trade name GORE-TEX.

The hydrophilic polyurethane layer selectively transfers water by diffusion but does not support pressure induced liquid flow. Therefore, although moisture is transferred, the continuous layer impedes the passage of microorganisms and air.

Polyurethanes useful in the present invention primarily comprise the product of polyols of oxyethylene units and polyisocyanates. Polyol groups are more than 45% by weight of the polyurethane, preferably more than 60% by weight, most preferably 70%
Make up more.

One class of such polyurethanes is polyurethanes having a polyoxyethylene backbone terminated with toluene diisocyanate groups. It has a branched polyester with at least 3 reactive isocyanate groups.

Another class of polyurethanes is (i) a polyol (A) having a number average molecular weight of from about 600 to about 3500 and having a functionality of at least 2; (ii) an isocyanate (B) having a functionality of at least 2. And (iii) a reaction product of a low molecular weight chain extender having a molecular weight in the range of less than about 500 and having a functionality of at least 2, wherein the reactant is of the formula: EqOH = EqCE EqCE 0, where EqNCO is the equivalent weight of the isocyanate species used and EqOH and EqCE are expressed as the molar equivalent weights of the polyol and chain extender used, respectively. Wherein the soft segment is provided primarily by a polyol of oxyethylene units, the preferred hard segment is provided by the reaction product of an isocyanate with a chain extender, and induces phase separation of the hard and soft segments. Including product.

(I) a polyol (A) predominantly oxyethylene units having a number average molecular weight of about 600 to about 3500; (ii) a polyisocyanate (B); and (iii) a low molecular weight diamine having a molecular weight in the range of less than about 500. Reaction products of functional chain extenders (C) are preferred.

(I) having a number average molecular weight of from about 600 to about 3500, poly (alkylene ether) glycols (A) predominantly oxyethylene units; (ii) diisocyanates (B); and (iii) molecular weights in the range of less than about 500. Most preferred are the reaction products of low molecular weight difunctional chain extenders (C) with.

These polyurethanes are described in detail in US Pat. No. 4,532,316.

To produce the product of the present invention, polyurethane is, in its liquid phase form, layered on top of the scaffold material and on one side of the scaffold material so as to partially penetrate the pores of the material. Applied. The substrate is mated with the polyurethane side of the polyurethane / scaffold combination (coating) and then solidified and / or cured with a secure bond between the substrate and the coating.

The coating method is described, but is not limited to the following description for a four roll stack as shown in FIG. Polyurethane metering is provided by the gravure roll 1 and the doctor blade / feed sump 10. Polyurethane 9 is applied to the continuously moving scaffold material 5 in a nip between two rotating rolls 2 and 3 in a controlled amount. One such rotating roll 2 carries a regulated amount of polyurethane and the other such roll 3 provides support to partially push the polyurethane into the porous structure of the scaffold material 5. The coating 7 (ie the combination of scaffold material and polyurethane) is combined with the substrate 6 in the nip between the two rotating rolls 3 and 4 to produce the coated product 8 of the present invention.
This method may be further improved such that the second substrate is placed on the back side of the coating to create a sandwich effect,
The coating is between the two substrates.

The pressure between rolls 2 and 3 and the amount of polyurethane flow are adjusted to provide a polyurethane that coats the surface of the scaffold material and penetrates the pores of the scaffold to a predetermined degree. However, be careful not to completely fill the pores of the microporous scaffold.

Referring to FIGS. 1 and 2, which show a representative coated product of the present invention, the substrate 1 is shown in FIG. 1 as a woven fabric made from fibers 2 and in FIG. 2 a nonwoven fabric. Indicated as. The raised or raised portion of the fabric is designated as 3. The polyurethane layer is shown as 4 and, as can be seen, contacts and adheres to the substrate at the raised or raised portions 3. The space in the cloth is shown as 8. The scaffold material is shown as 5, the pores are shown as 6 and are partially filled with polyurethane as shown at 7.

Coating (combination of polyurethane and scaffold material)
Are attached to the substrate in a unique way. The coating and substrate bond only at high specific locations. This is in contrast to what is usually found in the prior art, where the coating generally appears to follow the contours of the substrate and / or into the pores and valleys in the substrate, which alone It does not seem to have the specified overall thickness. In other words, on a microscopic scale, the coatings of the present invention appear to span between the contact points of the substrate, rather than following the contours of the surface.

It is believed that it is this phenomenon that causes good drape of the fabric. Drapability is defined as how the fabric sags when hung in different positions. Drapability is associated with flexibility and softness. Moreover, it is believed that it is the combination of scaffold and polyurethane that enables such a thin hydrophilic polyurethane layer to be so continuous. It is this continuity that provides the desired functional barrier properties as well as the thinness that enables such high water vapor transmission rates.

Although the products of the present invention find application in hospital gowns because of their good viral and bacterial barrier properties, they also have applications in hospital bedding, incontinence devices, hygiene products,
There are applications in other areas where such microbial barrier properties are desired and other similar areas.

The products of the present invention also provide utility in areas where airborne particulate barrier control is desired. For example, they have utility in asbestos cleaning where the operator is comfortable but needs to be protected. Changing the concept of protection,
The product also provides utility in that it keeps human body particles away from sensitive materials manufactured or used in the cleaning room.

The study of Laufman et al. (Am. Surg. 875, June 1975) was considered in the course of testing for bacterial and viral barriers for use in operating room garments. They measure the stress on the surgical barrier in use, 5 points (2.3 kg) on the elbow and 1 on the waist.
It has been found that the stress is on the order of 0 pounds (4.5 kg). The elbow area contains a circle with a diameter of 4 inches (10 cm),
Assuming that the waist covers a 36 inch (91 cm) area, these stresses are 0.40 psi (0.03 kg / cm ² ) and 0.
Equivalent to 28 psi (0.020 kg / cm ² ). To provide a degree of safety, the virus barrier test is 4 psi across the membrane specimen.
Performed at pressures up to g (0.3 kg / cm ² ).

Test Procedures A variety of different tests were used in the examples. They are,
It is explained below.

Air permeability measurement 100cc of air 6.45cm ² under a pressure drop of 1.2kPa
Gurl defined as the time (seconds) flowing through
The substrate and the product of the invention were tested for ey) seconds. Gurley seconds were converted to air permeability by dividing 100cc of air by the Gurley number. As such, air permeability is expressed in air (cc / min) in the test area. A test apparatus, a Gurley Densometer Model 4110 or Model 4120, was used in a manner similar to ASTM D726-58 Method A. Model 4110 was used for the uncoated substrate and Model 4120 was used for the coating test. The coated sample was oriented until the coated surface ensured a seal that was as effective as possible, but care should be taken to minimize leakage around the test area. As such, an air permeability of less than 6 cc / min was used herein as a reference indicating no air flow.

Water Vapor Transmission Test The test used to measure water vapor transmission rate (MVTR) is described below. The procedure has been found to be suitable for testing coatings and coated products.

During operation, a saturated salt solution of potassium acetate and distilled water about 70
ml was placed in a 133 ml polypropylene cup with an inner diameter of 6.5 cm by mouth. Gurley number about 7 seconds, foam P with a bubble point of about 179 kPa, measured as described in ASTM F316, a thickness of about 37 microns and a weight of about 20 g / m ^2.
A TFE membrane (available from WL Gore & Associates, Newark, Del.) Was heat sealed to the lip of the cup to form a tight, watertight, microporous barrier containing salt solution. . A similar foamed PTFE membrane was tautly mounted in a 12.5 cm embroidery hoop and floated on the surface of a water bath. The water bath assembly was adjusted to 23 ° C ± 0.1 ° C using a temperature controlled chamber and a water circulating bath.

The coated sample was then placed coated side down on the surface of the floating foamed PTFE membrane.

The cup assembly was calculated to approximately 1/1000 g and was placed in the reverse of the center of the test sample.

Water permeation is provided by the driving force between the water and the saturated salt solution, which gives the water flux by way of diffusion.
The sample was allowed to sit for 15 minutes, then the cup assembly was removed and weighed again to 1/1000 g.

The MVTR of the sample was calculated from the weight gain of the cup assembly and
It is expressed in g of water per 1 m ² of surface area of the sample per hour. The second cup assembly was simultaneously weighed to within 1/1000 g and placed on the test sample in the opposite direction. The test was repeated until a steady state MVTR was observed with two duplicate MVTR values. It has been found that with thin coatings (less than 0.25 mm) this generally requires only one test interval to obtain steady state information within test variability.

Suter Continuity Test The coated products of the present invention were tested for coating continuity using a modified Sooter test apparatus, a low water inlet pressure test. Water was pressed into a 10 cm diameter sample sealed by a rubber gasket placed in a clamp. The sample was mounted against the water, coated side down. It is important that a watertight seal is formed by the clamping mechanism, gasket and sample. In the deformable sample, the sample was held in place over the reinforced scrim (eg, open nonwoven scrim). The sample was exposed to atmospheric conditions and was visible to the operator. The water pressure on the sample was increased to 6.89 kPa by a pump connected to the sump, as indicated by the appropriate gauge, and controlled by an in-line valve. The test sample was at a predetermined angle and water was circulated to ensure contact with water and to ensure that air did not contact the underside of the sample. The top surface of the sample was visually observed for the appearance of the water forced into the sample over a period of at least 1 minute. The liquid water found on the surface was taken as a defect in the continuity of the coating. A pass grade is given if liquid water is not visible within 3 minutes, thus indicating a continuous coating.

Viral Barrier Efficiency Test To keep the barrier being tested, a jig was designed as shown in FIGS. 3 and 4.

Above the barrier, the virus suspension is contained in a pressurizable reservoir.

Below the barrier, the second reservoir contains the pumped tryptone broth, so that the bottom of the barrier is continuously washed with the broth. The washing solution is returned to the holding container for the culture solution. The upper reservoir is filled with virus suspension (at least 1 × 10 ⁸ virus particles / ml) and pressurized. The viral particles that pass through the barrier are washed into the culture medium. After a predetermined period, the culture is sampled for analysis.

To test for viral barriers, small icosahedral shaped bacteriophage (phi x 17 with a diameter of 27 nm
4) was used. The suspension was human serum. The test period applied to the virus suspension reservoir was 0.5-1 cm water pressure for 30 minutes, 4 cm water pressure for 30 minutes, 1 psig (0.07 kg / cm ² gauge pressure) for 30 minutes, and 4 psig (0.3 kg / cm ² gauge pressure) 30
It was a minute. At the beginning of each interval, sample the culture solution,
Then collected at the end.

Samples are serially diluted through 10 in tryptone medium for quantification. 0.5 ml of each dilution was added to 2.5 ml of autoclaved top agar in a sterile test tube, 1 drop of host bacterial suspension was added to each tube, mixed well and applied to the surface of the bottom agar plate. pour it up. 4 at 37 ± 2 ℃
Incubate for 12 hours to obtain large plaques that are sufficient to count but not enough to coalesce.

The phage titer was calculated from the plaque count and the result was PFU / m.
Record in l (units of plaque formation in 1 ml).

In addition, the increase in volume of circulating medium, which indicates the flow of liquid from the upper reservoir, should be noted.

Barrier efficiency is measured by observing the pressure at which virus leakage occurs at 4 psig (0.3 kg / cm ² gauge pressure).
The spill is judged as a failure. Pass 4psig (0.3kg / cm
^No leakage at ² gauge pressure).

The medium used is shown below.

Medium: Tryptone Medium: Bact-trypton 10.0g KCl ………………………… 5.0g CaCl ₂ ……………………… 0.15g Purified water …………… ……………… Adjust the pH to 7.3 with 2.5N NaOH, which is sufficient to make 1000 ml, and sterilize.

Top agar: Bact-agar …………………… 6.5g Trypton ………………………… 13.0g NaCl ………………………… 8.0g Glucose …………………… …… 3.0g Sodium citrate ………… 2.0g Purified water ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… Add each component in an amount sufficient to obtain 1000 ml. P with 2.5 N NaOH or NCl
Adjust to H7.5 and autoclave.

Bottom agar: Bact-agar …………………… 10.0g Trypton ………………………… 13.0g NaCl ………………………… 8.0g Glucose …………………… ...... 1.3g Sodium citrate ............ 2.0g Purified water …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… also of of each ingredient is added. PH 7.5 with 2.5N NaOH or HCl
Adjust, autoclave and pour into plates.

FIG. 2 is a drawing of the jig used for the virus barrier efficiency test. 1 is the barrier under test, 2 is the reservoir holding the virus suspension, 3 is the reservoir containing the detector solution, 4 is the inlet for circulating the detector solution, 5 is its It is the exit.

FIG. 3 is a representation of the device used to test barrier properties with a viral suspension. The upper reservoirs are equipped with respective outlet valves, pressure gauges and means for applying pressure to the virus suspension. The inlet 4 is connected to a peristaltic pump 6 that draws the detector solution from the supply container 7, and the outlet 5 supplies the detector liquid to 7. The liquid is
It is stirred and heated by the magnetic stirrer / heater 8.

Bacterial barrier challenge test A test method was devised considering the concepts of stress, surface tension, and liquid penetration.

The test is a diffusion technique where the barrier is clamped in place between two aqueous solutions. One solution contains the bacteria and the other solution is sterile. The purpose of this procedure is to determine if bacteria can contaminate the sterile solution by penetrating the barrier.

The stress is established by raising the fluid level during the challenge to half of the diffuser. The liquid used should be in the range of the surface tension of blood and body fluids. The sample is
It can be removed from the device over time without disturbing the sample or specimen. Different quality barriers can be distinguished by the choice of increased time or pressure. All results are obtained by serial dilution plating.
Indicated by a number.

The device consists of two chambers whose open sides fit together. Each chamber has a top inlet for introducing medium or for applying pressure to the chamber and each has a sample tap at the bottom. The barrier to be tested is placed between the open sides of the two chambers and these sides are clamped together. Challenge medium containing bacteria is introduced into one chamber of the sterilized diffusion device, while detector medium is added to the second chamber to prevent premature pressure gradients.

The level of challenge medium is adjusted to give it a positive pressure on the detector medium.

Samples are removed from the detector culture over time. At the end of the test, the entire contents of the detector chamber should be drained and mixed prior to plating. Overnight incubation of detector medium is used for very low count samples.

Samples are applied to agar with dilutions of 1,100,10,000 and 1,000,000. The result is CFU / ml (colony forming unit / m
Described in l).

Tripticase for these tests
E. coli at a concentration of 2 × 10 ⁸ CFU / ml in soybean culture was used as the challenge suspension. The exposure time was 30 minutes with a 4 inch (10 cm) hydrostatic head on challenge medium.

Example 1 A coated product was made in accordance with the present invention using the apparatus shown in FIG. The roll coater was used in a 4-roll stack arrangement in a line equipped with a winding device. The stack contains a gravure roll quadrilateral pattern, 33 cells per cm, cell depth 110 microns (33Q / 110), pressure nipped on polyurethane rubber rolls, pressure nipped on chrome rolls and pressed on silicone rubber rolls. It was pressure nipped. Gravuralol is a reactive prepared from 4,4'-diphenylmethane diisocyanate, polyoxyethylene having a number average molecular weight of 1450, and hydroquinone di (2-hydroxyethyl) ether prepared according to the teachings of U.S. Pat. No. 4,532,316. A trough containing hot melt hydrophilic polyurethane was provided. The melt viscosity of the polyurethane was about 2000 cps as measured with a rheometer using parallel reciprocating disks at an application temperature of 100 ° C. The hydrophilic polyurethane moved from the gravure roll along the stack until it contacted the scaffold material.
The scaffold material is a foamed PTFE prepared according to the teachings of US Pat. Nos. 3,953,566 and 4,187,390, having a weight of about 2-3 g / m ² and a porosity greater than 65%. It was The coating (ie, the combination of scaffold and polyurethane) was contacted with a 70 g / m ² pulp-filled spunlaced nonwoven polyester in a chrome roll / silicone roll nip. The coated product thus produced was then collected on a winding device. The coated product was then cured under ambient conditions for 48 hours. The product was aesthetically pleasing and had good drapeability. A representative photomicrograph (200x) can be seen in FIG. Commercially available
OR Gown, or American Converter (American C
The onverter OPTIMA fabric is representative of a pulp-filled spunlaced nonwoven polyester that is compared against the coated products of the present invention. The final properties of the coated product are shown in Table 1, along with Optima ™ substrate. All properties were characterized by the appropriate tests described above. The virus barrier efficiency test was carried out after 2.5 to 5 × Gaud ∽γ ray sterilization.

As can be seen from the data, highly moisture permeable products demonstrating the barrier properties described herein have been demonstrated.

Example 1 Example 2 To illustrate the utility of the present invention, the coated product described in Example 1 is compared in Table 2 with a structure currently sold to the protective clothing industry.

The following materials are representative of the materials sold for disposable use.

Sample 1 = non-woven polyolefin Sample 2 = two layers of non-woven polypropylene Sample 3 = spunlaced wood pulp polyester Sample 4 = spunlaced wood pulp polyester with polyethylene film reinforcement Other Sample 5 treated with liquid repellent High count (28
0) 50/50 polyester / cotton blend, which is representative of reusable products and was tested. All materials were tested as received.

As can be clearly seen, the product of the invention provides equal or superior protection to all of the other materials, and at the same time,
It gives an MVTR that is substantially equal to or greater than another material.

Example 3 To illustrate the flexibility of this product for substrate selection,
Various substrates were prepared as in Example 1.

Substrates shown: Sample 1 = 67 g / m ² spunlaced 100% polyester Sample 2 = 40 g / m ² spunlaced 100% polyester Sample 3 = 67 g / m ² point-bonded nylon Sample 4 = 42 g / m 2 The tricot knit data for ² is summarized in Table 3.

The moisture transmission obtained with the products of the invention is significantly higher. In many cases, the MVTR of the coated material is comparable to the uncoated substrate and additionally provides a functional barrier property that is not present in the substrate alone. Utilizing this feature of the invention, at least
A substrate having a MVTR of 5000g / m ^2/24 hours is selected, so that the substrate does not limit the high moisture vapor transmission rate.

Example 4 To illustrate the most preferred range of scaffold weight,
Three products of the invention were made as in Example 1 with the only difference being the scaffold weight used.

Example 5 The product of the invention can be provided with a microporous surface in the coating by one of two methods. The complete infiltration of the scaffold material is illustrated in Example 1. An alternative is to include a microporous layer as the second substrate and push it into the coating layer of the fully impregnated scaffold layer. This pushing operation is performed immediately downstream of the 4-roll stack shown in FIG. Table 5 compares the product of Example 1 with the product of Example 5.

Example 6 The sample of Example 5 was tested by the bacterial barrier challenge test to demonstrate that the functional barrier to microorganisms contained bacterial barrier properties. The barrier was found to be functional by having no detectable colony formation in any of the serial dilutions of the detected body fluid.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Bailey, Christian Edward 21904, Portland, Principe Lord 700, Maryland 21904, USA (72) Inventor Bowser, John Joseph United States, Delaware 19711, Newark, Meadow Circle 4 (72) Inventor Brown, Peter Lloyd, Maryland, United States 21921, Elkton, Jarmon Road 114

Claims (8)

[Claims] Containing 1. A (a) a porous scaffold material of a polymer having at least 5000g / m ^2/24 hr fabric base having a water vapor transmission rate, and (b) open microstructure of interconnected pores, A coating on at least one side of the base fabric, wherein the scaffold material has a porosity of at least 65% of the total scaffold material volume, and the scaffold has a weight of 1 to 10 grams per square meter. ,
The scaffold has a layer of hydrophilic polyurethane resin on one surface of the scaffold which extends into some of the pores of the scaffold and the polyurethane layer is 5-25 g.
A coated fabric, comprising a coating as described above, having a weight of 1 / m ² which allows passage of virus when tested by the virus barrier efficiency test at 0.28 kg / cm ² (4 psi). A coated fabric, which is a microbial buyer that does not allow the above, and is an airborne particulate barrier that exhibits an air passage rate of less than 6 cc / min. 2. A breathable garment that does not leak, comprising the article of claim 1. 3. A surgical gown comprising the article of claim 1. 4. A medical device comprising the article of claim 1. 5. A packaging material containing the article according to claim 1. 6. A diaper including the article according to claim 1. 7. A feminine hygiene product comprising the article of claim 1. 8. (a) a microporous scaffold material, wherein the hydrophilic polyurethane prepolymer forms a layer over the scaffold material and partially penetrates into the pores of the microporous scaffold material. A hydrophilic polyurethane prepolymer, and (b) contacting the substrate with a layer of prepolymer over the scaffold material while the prepolymer polymerizes. Method.